1. Field of the Invention
The present invention relates to a motor transmission apparatus provided between a drive shaft coupled to a drive wheel and a motor shaft coupled to a traction motor.
2. Description of the Related Art
A plurality of clutch mechanisms and brake mechanisms are incorporated into an automatic transmission or the like installed in a vehicle (see Japanese Patent Application Publication No. 2007-270954, for example). In these clutch mechanisms and brake mechanisms, engagement control must be performed while avoiding interlocking, in which gear trains having different gear ratios are engaged simultaneously.
Incidentally, in a hybrid vehicle that uses both an engine and a traction motor as drive sources or an electric automobile that uses a traction motor as a drive source, the traction motor must be prevented from over-speeding in order to suppress an induced voltage of the traction motor and thereby protect an inverter. By installing a transmission apparatus between the drive shaft and the traction motor, a rotation speed of the traction motor during high-speed travel can be reduced, and as a result, over-speeding can be prevented. The transmission apparatus for preventing over-speeding in the traction motor is also provided with a plurality of clutch mechanisms and brake mechanisms, and it is therefore important to employ a structure for preventing interlocking in the transmission apparatus.